Caine was found dead with a gunshot wound to his head at 3:07 a.m. Monday on Brookdale Avenue in the city's Visitacion Valley neighborhood, authorities said.

Zinn was killed six hours later in an apparent drive-by shooting as he stepped out of his home near Ironwood Way and Catalina Street in the Bayview about 9:30 a.m.

The slayings followed a series of shootings over the holiday weekend in the southeastern region of the city, including two that killed two other men.

Antonio Cortez, 37, of San Francisco died at San Francisco General Hospital three hours after he was shot on the 1700 block of La Salle Avenue in the Bayview at 2:54 a.m. Sunday. A 49-year-old unidentified man who was with him suffered life-threatening injuries.